Writing instrument



Nov. 11, 1952 M. KNQBEL WRITING INSTRUMENT *IN I Filed Jan. 17, 1947 8% wm p Patented Nov. 11, 1952 UNITED srr 7 RITIN G INSTRUMENT Maxf Knobel, Arlington,

Sheaier Pen Co., F

poration of Delaware Mass., assignor to W.A; ort Madison, Iowaa cor- Applicationmnuary 17, 1947,.seria1'-Nb; 722mg 2 Claims.

This invention relatesto a-writing instrument. More particularly, it is\conc`e'rned with an instrument of'the'type whichuti-lizes a b'all rotatable in a socket andA an ink-holdlngrreservoir for supplying ink to the ball for application to the Writing surface, together with `manual-means for applying pressure to theY ink system while writing and for relieving thispressure when-the pen is not in use.

Whenever the ink system isunder super-atmospheric pressure',` ink tends'to'feedfrom'the reservoir past the very small clearancel existing between the ball and socket notwithstanding the ball is not being rotatedasin writing. Those inevitable departures from perfect sphericity of the ball resulting from even the most carefully controlled methods of manufacture, toolv marks Within the ball socket and other factors' accentuate the problem. Even thoughthesocketis made as close as possible vto conform to the'surface of the ballwhile leaving a predetermined space for flow of ink, practicallimitations in mass manufacture will result inspace between the ball socket greater than needed for normal flow of ink as in writing-and; when the pen is not in use, so-calledweepage ofthe ink from the space between the ball and socket' becomes an annoyance. Theapplicationof feeding pressure upon the ink is a'dominantcause'of, or at least aggravates, Weepage While it is likelyv that weepage may exist, even though no pressure is applied, the problem of weepage' arises primarily where a pressure-feedtype ofballpoint writingl instrument is involved;

While the writing tip `or ball'may be protected to a considerable `degree by a cap, or by retraction of the tip into the'barrel, and damage to the users clothes by reasonof weepage thereby avoided, the ink accumulated onthe ball due to weepage may cause a blot or'smudge when writing is begun. Wiping ofthe pen before each use is obviously an undesirable precaution.

I have found that weepage may be eliminated by insuring that when the pen is in stand-by condition, the ink in the reservoir is under av pressure not greater than atmospheric, the`r desideratum being the' establishment of a pressure balance between the 'interior' and exterior" of' the reservoir so that there is "no tendency for theink to be forced from thepen; 'and' to this end, I provide' means operable' upon discontinuance of writing and'retraction ofthe'tipl automatically to create' a 'condition wherein 'atmospheric pressure is admitted "about the'ink reservoir. By em'- ploying such'm'eans,` the` pressure'upon the ink Cl. 1Z0-42.03)

and adjacentthe notendencyv` to f weepage exists. notanessential'f'eature of my thevtipbe retracta'ble,v since th disclosed" may function equally wellwith a-Writingfinstrument-of? the non-retractable type.

Moreover, itf is` desirable, before writing commences, to prime the's'ocke ball for the reason tha-tot stand-by condition may result i ume or pressure t'o* enable through the inters-ticeof the Flow of'ink past 'the lrimsurrou desirably initiatedi Wh`en` thev b as in writing.` By priming dition wherein the-pressure on the ink rearwardlyI of the rimfissuflieientto'enable vthe ballfto -receive an amount ofinkample for writing a-legi ble, unbroken line. I attain this object` by utilizing asingle device'operable'in two-senses, the actuation whereof-inone sense appliesslightly superatmospheric'- pressuretoliiiitiate ow of ink to thebalhand to-maintainlsuch condition during any one'v/ritingperio'd;v and actuation-in the other sense'relie obviate weepage.

Accordingly, tion is the prov example, one i having an ink applying sligh the' body of i writing and t writing'.

Another object is toV either independentl aforesaid pressurethat the body of i tioned at atmosph out vof use.

Still anotherv ob strumentwhich tract type, i; e. be maintainedi barrel during n However, it is n insuicient volimmediate flow ballV and socket. riding the-balli is Il refer to a-- conision in: awriting instrument, for ncludin'ga balll writingy tip, and

tly superatmospheric pressure to nk in the reservoir preliminary to o improve'theow thereof during provide pneumatic means y of or cojointly with the applying means for insuring nkin the reservoir is condiericV pressure when the pen is ject-is to'r providea- Writing inmay b'e termed the project-reinwhich the'writingtip may on-use, and propelled or projected out of the barrelfor writing, in which instrumentv the meansv for' propelling the tip is simultaneously effectivel to actuate" pneumatic means for subjectingv the ink' to'slightly superatmospheric pressure.

A furtherY object-is t strument of the proj tip-'retracting means ders`A the pneumatic'm Ojprovide va writing inect-retract type having balland socketisfe'qualized and I invention thatV e means hereinA th rearwardlyv ofi the herwisev a prolongedall begins to roll ves suchexcess pressure toa principal object of my invenreservoir, of improved means for' n ai shielded position within thev which simultaneously reneans ineffective and' thus relieves the pressure on the body of ink in the reservoir.

An additional object is to provide a writing instrument as in the foregoing paragraph in which the pressure-relieving means is so constructed and arranged as to expose the ink reservoir therein to atmosphere.

provide a writing instrument with means by which the same is conditioned for writing by pro,ecting the normally shielded writing-tip exteriorly of the barrel for writing, while simultaneously or slightly before or after such projection, the body of ink is subjected to a pressure above atmospheric to initiate feeding of the ink, the non-writing condition being such that the body of ink is under atmospheric pressure. Thus a minor degree of acceleration is imparted to the flowing ink to insure immediate response of the pen to the writing action. Such means preferably includes a plunger operable within a cylinder forming part ofthe ink-sac enclosing structure. The instrument, in a preferred form, is also constructed and arranged in such manner that upon retraction of the writing point to shielded, i. e., non-writing position, the plunger is reversely operated to open a vent to atmosphere in order to terminate the pressure-induced flow of ink and thereby avoid weepage at the writing tip.

In what follows, the description will, by way of exemplication, refer to a writing instrument of the ball-tip class to which an ink reservoir is connected, the tip being movable out of or into a supporting barrel for writing or stand-by. For convenience in the description and claims, a structure possessing this characteristic will be hereinafter referred to as of the project-retract type.

In the drawing which shows the aforesaid preferred embodiment of my invention:

Fig. 1 shows a longitudinal mid-cross section of the instrument with certain parts in elevation and the pen prepared for writing, the view being broken to conform to limitations of sheet size while maintaining a readable scale of the parts; l

Fig. 2 shows a partial section similar to that of Fig. 1 but with the parts in the position corresponding to a retracted or shielded condition of the writing-tip, and

Fig. 3 is a detail view taken in the direction of the arrows 3-3 of Fig. 1.

Referring now to the drawing, that form of my invention there illustrated comprises a cylindrir cal barrel 9 of any suitable material within the forward end I of which is secured a bushing Adapted to slide within the aperture I2 thereof is the body I3 of what is herein referred to as the sac section, which latter includes a fiaccid or iiexible ink reservoir or sac I4 of fabric, rubber, or combination thereof, or any other material suitablerfor the purpose, retained on a reduced part I5 of the body I3 by a band IG of metal, plastic or other material, there being a peripheral groove to insure locking of the sac to the part I5.. In order to protect and support the sac I4, the same is enclosed in a metallic cylindrical casing 2| fitted over the body I3 and secured thereto by being spun into a peripheral groove 22 therein.

At its forward end, the body I3 has a threaded aperture 24 into which is threadedly engaged the tip portion 25 having an axial ink passage 26 in communication with the socket or ball seat 21,

the latter supporting the rotatable writing tip, preferably a ball 28, and the metal at the extremity being spun over the ball to retain the same in position therein. A minute clearance is provided between the ball and socket to permit ink iiow.

Barrel 9 is most conveniently comprised of two halves for ease in manufacture and assembly, there being the forward part III heretofore noted and a rearward part 3|, the interconnection therebetween being effected by securing within the part I0 a bushing 32 having a threaded neck with which a correspondingly threaded sleeve 33 secured within the part 3| may be engaged and the two parts of the barrel, upon assembly, drawn into snug union. Bushing 32 by engagement with the casing 2| also serves to slidably support the sac section at its rearward extremity.

As will appear hereinafter, the instrument herein shown and described as one form in which my invention may be embodied is of the projectretract type. Accordingly, to provide retractive force upon release of the locking mechanism to be described, there is a helical spring 34 interposed between the bushing and a shoulder 35 of the body I3.

For projecting and retracting the writing-tip with respect to the barrel, there is provided a cylindrical operating member 4| including a body part 42, and a button 43 secured thereto by dimpling the same into an aperture 44. Member 4| is both axially and rotatably shiftable with respect to the barrel 9 and is guided forwardly in a bushing 45 pressed into the barrel part 3| and rearwardly within the open end of the barrel as shown.

The instrument is provided with the usual pocket-engaging clip 5| locked with respect to the barrel 9 by a key 52, the details of construction of the clip and key forming no part of the present invention. To clear the clip and Akey during rotation and sliding, the body part 42 is cut out as shown at 53.

The writing-tip is adapted to be locked in projected position (Fig. 1), and for that purpose, the bushing 46 is provided with a bayonet or stepped slot 54 with which a struck-out lip 55 of the part 42 is engageable in a manner to be described. Propulsive force imparted to the member 4| is transmitted to the sac section through the medium of a spring, preferably a conical coil spring 56.

Adapted to reduce the volume of air space within the casing 2| is a plunger or piston 6| of synthetic or natural rubber or equivalent suitable material, snugly slidable in the casing and cemented or otherwise joined to a disk or backing plate 62 secured to a piston rod 63, the latter passing through and guided by an aperture 64 in the fixed rear closure 65 of the casing 2|, and the rear extremity of the rod 63 being secured, as by peening, within a disk 45 adapted to abut the forward end of the part 42. In the wall of the casing 2|, and positioned so as to cooperate with the plunger 6| in a manner to be described, is a vent aperture 66.

In order to limit rearward shifting of the casing 2| and the parts movable therewith, the same is provided with an integral flange 68 adapted to abut a lug 69 extending from the bushing 46.

Operation of the instrument is as follows: As shown in Fig. 1, the writing-tip is projected and the pen is ready for use. In Fig. 2, the mechanism is shown wherein the tip is retracted and the pen is in non-writing condition with the tip acides? tinued movement of thejmember subsequently,

thrusts the sac section andtipffrwardly against the urging of the spring 34 until the tip is exposed (Fig. 1), at which time lip 55 is locked in slot 54 as described. During inward movement of the member 4|, the piston rod 63 and plunger 6| are operated to slide the plunger with respect to the casing 2|, thereby to compress the body of air intermediate the casing and the sac |4. Accordingly, pressure above atmospheric thus applied to the sac will compress the same and its contained inl; to furnish an adequate supply of ink in the socket to insure a proper supply of ink at the commencement of, and during Writing. It will be understood that the proportioning of the movement of the plunger with respect to the casing must be such as just to initiate and assist in maintaining ink now, but not sufficient to eject the ink in a quantity which may result in a blot or smudge. Furthermore, it should be noted that the plunger means functions not only to initiate ink flow but to maintain ink ow during writing, thus yielding all of the advantages of a pressurized ink-feeding system.

Upon completion of use, the writing-tip is retracted by rotation of the button in a, counterclockwise sense whereupon the lip 55 is released for return against the rearward step '54h of the slot 54 and the sac section is forced rearwardly under bias of the spring 34 to come to a stop by abutment of the ange 68 with the lug 69. During expansion of the spring 34, the spring'56 also expands to return the member 4| to extreme rearward position (Fig. 2). Simultaneously, with the movement of member 4| -to the rear (the sac section including casing 2| being then immobile), plunger 6| is also moved rearwardly relative to the casing 2| to expose the vent aperture 66, the same having been closed upon forward movement of the plunger. Thus the space within the casing and surrounding the sac is placed in communication with atmosphere. Consequently, there being atmospheric pressure at the ball and socket, as well as on the sac, ink is prevented from owing, and the instrument may be safely carried without danger of weepage. Fig. 2 shows the plunger in returned position and exposing the vent 66.

It is to be understood that spring 56 is provided only to return member 4| to released position and thereby to actuate the plunger 6| relative to the casing 2|, and for that reason, has less bias than the spring 34.

The construction and arrangement of parts herein shown and described for preliminary forced feeding of the ink and for preventing weepage when the pen is in stand-by condition, while shown incorporated in an instrument wherein the writing-tip is of the project-retract type is equally applicable to a pen in which the writing-tip is immovable. In such embodiment, the member 4| will be utilized only to actuate the plunger with respect to the fixed sac-enclosing casing,- the mode of operationfbeing-obvious-front the` preceding nzlescrilatiorn`4 Particularly outstandir'ig-v advantages of the-devicev herein disclosed #aref thatv ity affords-apressurized systeml for writing and theA non-weepage advantage vof a mere gravity system during the intervals of rest.Y In the deviceillustrated in the drawing, there isV no need of anything to remind theuser to putpressure on the .inlcsince this is done when the tip is projected.. Likewise the4 pressure is.` automatically released-,when the tipv is retracted to the non-use pOStion.

WhileI have shown particular embodiments of? my invention, it will be understood, of course, that I do not Wish to be limited thereto since many modifications may be made, and I therefore con-- template by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. A writing instrument comprising in combination a barrel, a section including the Writing tip and having a flexible ink reservoir carried by said section and in fluid communication with said tip, a sleeve surrounding said reservoir sealed at one end with respect to said section and having a vent open to atmosphere in the wall thereof, said section being slidable within said barrel for projection of said tip to writing position or retraction thereof for stand-by, a resilient element interposed between said barrel and section normally urging said section to stand-by position, a member slidable in said barrel and having a plunger afxed thereto, said plunger being operable within said sleeve, a second resilient element intermediate said sleeve and member, said member when thrust in the direction of said tip being effective to project the same to writing position and to cause said plunger to apply superatmospheric pressure to the ink in said reservoir, releasable means for locking said member in said thrust position, and said rst resilient element being effective upon unlocking of said releasable means to retract the tip, and said second resilient element being effective to move said plunger to uncover said vent and thereby subject said ink to atmospheric pressure.

2. A writing instrument comprising in combination a barrel, a section including a writing tip and having a flexible ink reservoir carried by said section and in fluid communication with said tip, a sleeve surrounding said reservoir sealed at one end with respect to said section and having a vent open to the atmosphere in the wall thereof, said section being slidable within said barrel for projection of said tip to writing position or retraction thereof for stand-by, a resilient element interposed between said barrel and said section normally urging said section to stand-by position, a piston rod having an enlarged rearward end slidable axially in said barrel and having an enlarged plunger afxed on the forward end thereof, said plunger being operable within said sleeve, a compression spring encircling said piston rod intermediat. said enlarged rearward end and said sleeve, said piston rod and plunger when thrust in the direction of said tip being effective to project the same to writing position and to cause said plunger to close said vent and to apply superatmospheric pressure on the ink in said reservoir, releasable means for locking said piston rod and said plunger in said thrust and pressure-applying position, said resilient element being elective upon unlocking of said releasable means to retract said tip, and said compression spring being elective to move said piston rod and plunger axially of said sleeve whereby to uncover said vent and to freely vent said sleeve to the atmosphere.

MAX KNOBEL.

Name Date Hoffman Dec. 1, 1885 Number Number Number Name Date Cowger Feb. 9, 1897 Schmidt Mar. 6, 1923 Hudson Dec. 22, 1925 Randolph Sept. 9, 1947 Chesler Dec. 2, 1947 Chesler June 22, 1948 Wahl Sept. 27, 1949 Wahl May 8. 1951 FOREIGN PATENTS Country Date Switzerland Oct. 16, 1942 

